Stacking TC - samples

[marekjoz]

There are some questions regarding teleconverters - IQ achieved, AF, apperture etc. Having read great Tale of Two Teleconverters http://www.billmajoros.com/photoalbum/categories/new/Teleconverters/index.html I made a test myself.

Assumptions:
1. Controlled lighting environment
2. Tripod
3. Mirror up
4. Remote shutter
5. Several shots with different appertures, shutter speeds, liveview - best shot chosen
6. No sharpening, contrast etc.=0, DPP from RAW to JPG, Quality=10

Gear used: 7D, EF 70-200 F4 LIS (IS off), EF1.4II, EF2.0II

Below you will find the result in three sections
A. 100% crop of some area possible to make comparisons, constant width=500px
B. Almost the same area, different file sizes
C. Almost same area, JPG downsized to width=500px

Below in this post images from section A:
100% crop of some area possible to make comparisons, constant width=500px

[marekjoz]

Section B  Almost the same area, different file sizes

[marekjoz]

C. Almost same area, JPG downsized to width=500px

[marekjoz]

I know you can find a lot of such comparisons in Internet. As I still have both TCs and someone would have some questions, I can check or make some additional comparisons (with 5d2 ie)

My conclusion:
1. If you want to shoot some static object and can afford preparations taking up to 15 seconds for each shot - you can stack teleconverters as IQ doesn't drop (on this lens with 7d). I'd say - it's even better if you need to crop but I didn't check it with another lens or with 5d2 as far.
2. No AF here, so tripod, mirror up, remote shooting and no wind are absolutely important

Any questions or suggestions highly appreciated

[K-amps]

I know you can find a lot of such comparisons in Internet. As I still have both TCs and someone would have some questions, I can check or make some additional comparisons (with 5d2 ie)

My conclusion:
1. If you want to shoot some static object and can afford preparations taking up to 15 seconds for each shot - you can stack teleconverters as IQ doesn't drop (on this lens with 7d). I'd say - it's even better if you need to crop but I didn't check it with another lens or with 5d2 as far.
2. No AF here, so tripod, mirror up, remore shooting and no wind are absolutely important

Any questions or suggestions highly appreciated

Thanks for posting your results!

[akiskev]

Thanks for this test! I found it very useful!

[AnselA]

Nice job.

[Beautor]

Thanks for posting your test and results. Its not what I would have expected.

[marekjoz]

Thanks for posting your test and results. Its not what I would have expected.

I'm going to repeat this test including 5d2. I expect on 5d2 see IQ degradation.

BTW: What I didn't mention before - crops are almost from the center of the image only.

[Mt Spokane Photography]

I see the IQ degradation toward the edges, however, I have no problems using the TC's with my 70-200mm f/4 L, it takes them pretty well.
 
Being a crop camera, it only gets the center part of the image, so that helps
 
These were taken using AF and hand held.  IS was on.
 
70-200mm f/4L IS 1.4X TC and 1D MK III
 

 
 
 
70-200mm f/4 L IS  2X TC on 1D MK III
 

 
 
 
 
70-200mm f/4 L IS  1.4X + 2X TC on 1D MK III